A cold modern request succeeds with no prior handshake

How to fix this

Answer a request that arrives cold, with no prior handshake. `initialize` and `notifications/initialized` were removed; every request is self-contained.

How the validator checks this

Probe P1.1, against a streamable-http server on the modern protocol. What it reports:

pass

Cold request succeeded with no prior handshake

Quoted from the probe that runs this check, so it cannot drift from what the validator actually reports.

This rule is checked deterministically: a fail here is a certain violation, not an inference.

Checked in the same request as MCP-DSC-001, MCP-DSC-002, MCP-DSC-003, MCP-DSC-004, MCP-DSC-005, MCP-RES-001, MCP-RES-002, MCP-RES-005.

Check your own server against this rule

The validator makes real protocol requests and reports this rule as pass, warn or fail alongside the other 78. Validate a server or read how the check works.

Other Statelessness and session removal rules

• MCP-STL-001Server never mints or echoes Mcp-Session-Id
• MCP-STL-002A client-supplied Mcp-Session-Id is ignored, not required
• MCP-STL-004Server does not rely on prior requests over the same connection
• MCP-STL-005GET on the MCP endpoint returns 405
• MCP-STL-006DELETE on the MCP endpoint returns 405
• MCP-STL-007Last-Event-ID is ignored — streams are not resumable
• MCP-STL-008tools/list does not vary per connection